In my U.S. Pat. Nos. 3,401,693; 3,682,174; 3,757,779; 3,413,974 and 4,009,716, description is made of disposable hypodermic syringes having a barrel, the open end of which is sealed by a sealing disc member. A hollow needle is mounted within a removable cover, which aseptically houses the needle while protecting the needle against damage during periods of non-use. Means are provided for mounting the needle within the cover for piercing the sealing disc in order to gain access to the interior of the barrel to beyond the portion of the needle projecting through the sealing disc into communication with the liquid content material in the barrel. Thus the fluid or liquid content material may be dispensed from the barrel, through the needle in response to pressure applied by the various means described in the aforementioned patents.
In my previously issued U.S. Pat. Nos. 3,557,787; 3,678,931; 3,682,174; 3,757,779; 3,779,371; 3,785,397; 3,838,689; 4,055,177, and 4,234,083, description is made of a hypodermic syringe in which materials in measured amounts are contained in separate compartments with means for combining the materials in a single compartment immediately prior to use for injection of the formed solution or dispersion that is formed without exposure to elements which might otherwise bring about contamination. As in the devices previously described, the open end of the last compartment, in the form of a barrel, is sealed by a sealing disc member adapted to be pierced by a hollow needle whereby the formed solution or dispersion can be dispensed through the needle for injection and the like.
In the devices of the types described, use is made of a hollow needle, which is mounted in a hub assembly wherein the inner end of the needle is spaced a short distance from the sealing disc in order to pierce the sealing disc in response to rearward displacement of the hollow needle. Such displacement to pierce the sealing disc can be effected manually by axial displacement of the hub in which the needle is mounted, or automatically in response to the release of the needle held under tension within the hub, as by means of a spring.
In general, as described in U.S. Pat. No. 4,009,716, use is made of a ferrule and a needle hub assembly having a threaded portion at one end which threadably engages an internally threaded portion of the needle cover. The arrangement is such that, during assembly, the needle is urged to an advanced position against action of the spring or other resilient means carried by the ferrule. This enables the threaded portion of the hub to be engaged by the internally threaded portion of the cover when the latter is secured in place. The cover thus engages the ferrule to maintain the latter in the advanced position until the cover is unscrewed. This frees the ferrule to enable the spring to snap towards its relaxed position whereby the needle is projected rearwardly to bar the sealing disc member to penetrate into the barrel for communication with the interior and the material contained therein.
One of the problems in the use of assemblies of the type described, when used as a syringe, vial, or infusion bottle, resides in the tendency for the hollow needle to core the rubber sealing member as the needle is projected therethrough. The minute section or sliver cored from the rubber sealing member can plug the cannula to interfere with the flow of liquid or fluid through the needle and/or, if small enough, it can become entrained in the fluid or liquid as it is being dispensed from the device into the patient. The entrained rubber particle represents a foreign body. If the solution enters a blood stream, the potential danger is increased.
It is an object of this invention to provide a device of the type described wherein communication between the hollow needle and the fluid or liquid that is in the barrel can be effected without requiring the needle to pierce the sealing disc, thereby to avoid the danger heretofore described.
It is another object of this invention to provide a device of the type described, such as a syringe, vial, or infusion bottle in which use is made of a disc member.
It is another object of this invention to provide a device of the type described, such as a syringe, vial or infusion bottle, in which use is made of a disc member sealing the barrel but which instead is fabricated with sealing means displaceable within the barrel itself between a sealing position, separating the liquid within the barrel from the needle, and an unsealed position which enables the liquid to flow from the barrel into communication with the needle to enable liquid to be dispensed from the barrel and through the needle.